feat(challenges): add caesar-cipher

challenges/caesar-cipher/README.md

@@ -0,0 +1,34 @@
+# caesar-cipher
+
+Created by [@Divlo](https://github.com/Divlo) on 25 June 2021.
+
+## Instructions
+
+In cryptography, a Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of -3, D would be replaced by A, E would become B, and so on. The method is named after Julius Caesar, who used it in his private correspondence.
+
+### Example of the alphabet with a shift of +3 (shift to the right)
+
+```text
+Alphabet original   : ABCDEFGHIJKLMNOPQRSTUVWXYZ
+Alphabet rotated +3 : DEFGHIJKLMNOPQRSTUVWXYZABC
+```
+
+Create a function that will return the sentence after shifting the alphabet.
+
+- If it is a **positive** number then we shift the alphabet to the **right**
+- If it is a **negative** number then we shift the alphabet to the **left**
+
+### Example of Inputs
+
+```py
+'ANTHONY' # a character string (all capital letters)
+'-2' # an integer, the shift in the alphabet
+```
+
+## Source
+
+- [Wikipedia - Caesar cipher](https://en.wikipedia.org/wiki/Caesar_cipher)
+
+## Examples
+
+See the `test` folder for examples of input/output.

challenges/caesar-cipher/test/1/input.txt

@@ -0,0 +1,2 @@
+ANTHONY
+-2

challenges/caesar-cipher/test/1/output.txt

@@ -0,0 +1 @@
+YLRFMLW

challenges/caesar-cipher/test/2/input.txt

@@ -0,0 +1,2 @@
+THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG
+-23

challenges/caesar-cipher/test/2/output.txt

@@ -0,0 +1 @@
+WKH TXLFN EURZQ IRA MXPSV RYHU WKH ODCB GRJ

challenges/caesar-cipher/test/3/input.txt

@@ -0,0 +1,2 @@
+PROGRAMMING CHALLENGES IS AWESOME
+-12

challenges/caesar-cipher/test/3/output.txt

@@ -0,0 +1 @@
+DFCUFOAAWBU QVOZZSBUSG WG OKSGCAS

challenges/caesar-cipher/test/4/input.txt

@@ -0,0 +1,2 @@
+JVUNYHABSHAPVUZ
+-19

challenges/caesar-cipher/test/4/output.txt

@@ -0,0 +1 @@
+QCBUFOHIZOHWCBG

challenges/caesar-cipher/test/5/input.txt

@@ -0,0 +1,2 @@
+JAVASCRIPT
+-11

challenges/caesar-cipher/test/5/output.txt

@@ -0,0 +1 @@
+YPKPHRGXEI

challenges/caesar-cipher/test/6/input.txt

@@ -0,0 +1,2 @@
+HEY
+5

challenges/caesar-cipher/test/6/output.txt

@@ -0,0 +1 @@
+MJD

challenges/caesar-cipher/test/7/input.txt

@@ -0,0 +1,2 @@
+CODING DOJO
+0

challenges/caesar-cipher/test/7/output.txt

@@ -0,0 +1 @@
+CODING DOJO